I got that FW by dumb luck. A dealer was the only other interested bidder and he was too cheap to pay a fair price..
I check GI daily and have gotten lucky there but because I'm not constantly scanning it I've missed more than I've bought. The best sellers are listing on GI but there ain't no bargains from them. GB is full of junk and a buyer can get burned very easily if he isn't careful. There is no substitute for having the gun in hand before forking over the cash..gun shows are the best place for that though not as convenient as sitting at the computer.
A 3 day inspection is only as good as the seller's character. Doing business with established sellers is the safest policy but still not 100% foolproof. There's a few bad apples in their ranks..especially on the high dollar stuff...
On another note...there's an 8MM (7.92) Mauser 70 just listed on GI which is a very scarce caliber. Any hard core 70 collector should have a look at it...
